| (19) |
 |
|
(11) |
EP 0 260 020 A3 |
| (12) |
EUROPEAN PATENT APPLICATION |
| (88) |
Date of publication A3: |
|
27.09.1989 Bulletin 1989/39 |
| (43) |
Date of publication A2: |
|
16.03.1988 Bulletin 1988/11 |
| (22) |
Date of filing: 25.08.1987 |
|
| (51) |
International Patent Classification (IPC)4: H04N 1/40 |
|
| (84) |
Designated Contracting States: |
|
DE FR GB |
| (30) |
Priority: |
25.08.1986 US 899358
|
| (71) |
Applicant: Hewlett-Packard Company |
|
Palo Alto,
California 94304 (US) |
|
| (72) |
Inventors: |
|
- Dispoto, Gary J.
Mountain View
California 94043 (US)
- Mather, Larry R.
Menlo Park
California 94025 (US)
- Meyer, John D.
Mountain View
California 94041 (US)
|
| (74) |
Representative: Williams, John Francis et al |
|
WILLIAMS, POWELL & ASSOCIATES
34 Tavistock Street
London WC2E 7PB
London WC2E 7PB (GB) |
|
| |
|
| (54) |
A method of generating a gray scale image |
(57) A method and apparatus for generating a grey scale image using a matrix of pixels
uses dots of differing sizes to represent different grey levels. When there is no
exact match between the dot size and the grey level of the original, an error magnitude
is determined and the error is then scaled and diffused to alter the dot sizes of
adjacent pixels.